title: Single-measurement therapeutic drug monitoring of the HIV/AIDS drugs abacavir, zidovudine, lamivudine, efavirenz, nevirapine, lopinavir and nelfinavir.
abstract: BACKGROUND
  There is currently no consensus about the significance of therapeutic drug monitoring (TDM) in the management of human immunodeficiency virus (HIV) infection.
  
  
  OBJECTIVE
  In this study, single drug levels from routine clinical samples were determined in order to add further data on the therapeutic plasma level range and on drug levels under anti-HIV therapy in general.
  
  
  METHODS
  A total of 215 plasma samples obtained from patients with HIV infection for whom TDM was requested for the first time were evaluated. Plasma values were determined for abacavir and zidovudine between 1 and 3 h after drug intake. Lamivudine, efavirenz, nevirapine, lopinavir and nelfinavir plasma values were determined between 1 and 12 h after drug intake. Drug levels were determined with a home-brewed assay based on high-performance liquid chromatography.
  
  
  RESULTS
  Plasma concentrations of HIV drugs showed a large variability. Plasma concentrations of abacavir, zidovudine and lamivudine were found to be similar to those reported recently. For efavirenz and nevirapine, 37 and 61% of the samples did not meet the minimum trough levels suggested. For lopinavir and nelfinavir, the majority of the samples (78 and 80%) were found to be within the therapeutic plasma level range.
  
  
  CONCLUSIONS
  Despite a large variation of anti-HIV drug plasma concentrations, single-measurement TDM may be sufficient in the routine management of the majority of patients.
authors.affiliation: Institute of Experimental and Clinical Pharmacology, Medical University Graz, Graz, Austria. josef.donnerer@meduni-graz.at
authors.forename: Josef
authors.initials: J
authors.lastname: Donnerer
authors.forename: Bernhard J
authors.initials: BJ
authors.lastname: Haas
authors.forename: Harald H
authors.initials: HH
authors.lastname: Kessler
mesh_terms: D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors
chemical_list: D019380:Anti-HIV Agents